GFS is especially useful when the physical location of two or more computers are located in distant locations and they cannot directly share a file or group of files. A global file system saves the changes made by one system and displays the changes on all the systems sharing it. It is the same as a distributed file system, except that the nodes have direct access to the data. A GFS reads and writes to the remote device, similarly to a local file system, and also permits the computers to organize their I/O to preserve file system uniformity.